IL-4 receptor alpha is an important modulator of IL-4 and IL-13 receptor binding: implications for the development of therapeutic targets

A Review of Dupilumab in the Treatment of Atopic Dermatitis in Infants and Children

Atopic dermatitis (AD), a common pruritic and chronic inflammatory skin disease, has a major impact on a patient's quality of life. It is characterized by dry, itchy, and eczema-like rashes. AD is more prevalent in young children and has been linked to a variety of other allergy disorders. Traditional drug therapy has certain limitations for treating young children with AD. However, biologics have good clinical application prospects in the medical treatment of young patients. Dupilumab, a fully human monoclonal antibody, specifically binds to the IL-4 Rα subunit, inhibiting IL-4 and IL-13 signaling and blocking the occurrence of type 2 inflammatory response. It has a good effect on treating infants and children with moderate-to-severe AD. This review explores the safety and efficacy of dupilumab in the treatment of AD in infants and children and the impact of early intervention on AD progression, with the aim of informing clinical practice in the use of dupilumab for the treatment of young patients with AD.

Immunology and pathology of echinostomes and other intestinal trematodes

Intestinal trematodes constitute a major group of helminths that parasitize humans and animals with relevant morbidity and mortality. Despite the importance of the intestinal trematodes in medical and veterinary sciences, immunology and pathology of these helminth infections have been neglected for years. Apart from the work focused on the members of the family Echnistomatidae, there are only very isolated and sporadic studies on the representatives of other families of digeneans, which makes a compilation of all these studies necessary. In the present review, the most salient literature on the immunology and pathology of intestinal trematodes in their definitive hosts in examined. Emphasis will be placed on members of the echinostomatidae family, since it is the group in which the most work has been carried out. However, we also review the information on selected species of the families Brachylaimidae, Diplostomidae, Gymnophallidae, and Heterophyidae. For most of these families, coverage is considered under the following headings: (i) Background; (ii) Pathology of the infection; (iii) Immunology of the infection; and (iv) Human infections.

Type 2 innate lymphoid cells are not involved in mouse bladder tumor development

Therapies for bladder cancer patients are limited by side effects and failures, highlighting the need for novel targets to improve disease management. Given the emerging evidence highlighting the key role of innate lymphoid cell subsets, especially type 2 innate lymphoid cells (ILC2s), in shaping the tumor microenvironment and immune responses, we investigated the contribution of ILC2s in bladder tumor development. Using the orthotopic murine MB49 bladder tumor model, we found a strong enrichment of ILC2s in the bladder under steady-state conditions, comparable to that in the lung. However, as tumors grew, we observed an increase in ILC1s but no changes in ILC2s. Targeting ILC2s by blocking IL-4/IL-13 signaling pathways, IL-5, or IL-33 receptor, or using IL-33-deficient or ILC2-deficient mice, did not affect mice survival following bladder tumor implantation. Overall, these results suggest that ILC2s do not contribute significantly to bladder tumor development, yet further investigations are required to confirm these results in bladder cancer patients.

Engineering the IL-4/IL-13 axis for targeted immune modulation

The structurally and functionally related interleukin-4 (IL-4) and IL-13 cytokines play pivotal roles in shaping immune activity. The IL-4/IL-13 axis is best known for its critical role in T helper 2 (Th2) cell-mediated Type 2 inflammation, which protects the host from large multicellular pathogens, such as parasitic helminth worms, and regulates immune responses to allergens. In addition, IL-4 and IL-13 stimulate a wide range of innate and adaptive immune cells, as well as non-hematopoietic cells, to coordinate various functions, including immune regulation, antibody production, and fibrosis. Due to its importance for a broad spectrum of physiological activities, the IL-4/IL-13 network has been targeted through a variety of molecular engineering and synthetic biology approaches to modulate immune behavior and develop novel therapeutics. Here, we review ongoing efforts to manipulate the IL-4/IL-13 axis, including cytokine engineering strategies, formulation of fusion proteins, antagonist development, cell engineering approaches, and biosensor design. We discuss how these strategies have been employed to dissect IL-4 and IL-13 pathways, as well as to discover new immunotherapies targeting allergy, autoimmune diseases, and cancer. Looking ahead, emerging bioengineering tools promise to continue advancing fundamental understanding of IL-4/IL-13 biology and enabling researchers to exploit these insights to develop effective interventions.

Molecular and cellular factors determining the functional pleiotropy of cytokines

Cytokines are soluble factors vital for mammalian physiology. Cytokines elicit highly pleiotropic activities, characterized by their ability to induce a wide spectrum of functional responses in a diverse range of cell subsets, which makes their study very challenging. Cytokines activate signalling via receptor dimerization/oligomerization, triggering activation of the JAK (Janus kinase)/STAT (signal transducer and activator of transcription) signalling pathway. Given the strong crosstalk and shared usage of key components of cytokine signalling pathways, a long-standing question in the field pertains to how functional diversity is achieved by cytokines. Here, we discuss how biophysical - for example, ligand-receptor binding affinity and topology - and cellular - for example, receptor, JAK and STAT protein levels, endosomal compartment - parameters contribute to the modulation and diversification of cytokine responses. We review how these parameters ultimately converge into a common mechanism to fine-tune cytokine signalling that involves the control of the number of Tyr residues phosphorylated in the receptor intracellular domain upon cytokine stimulation. This results in different kinetics of STAT activation, and induction of specific gene expression programs, ensuring the generation of functional diversity by cytokines using a limited set of signalling intermediaries. We describe how these first principles of cytokine signalling have been exploited using protein engineering to design cytokine variants with more specific and less toxic responses for immunotherapy.

Interleukin-2 family cytokines: An overview of genes, expression, signaling and functional roles in teleost

The interleukin-2 (IL-2) family cytokines include IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21, which share γ chain (γc) subunit in receptors. The IL-2 family cytokines have unique biological effects that regulate differentiation, survival and activation of multiple lymphocyte lineages. Deficiency of IL-2 family signaling pathway in mammals prevents CD4⁺ T cells from developing effector functions and CD8⁺ T cells from developing immunological memory. In the present review, we addressed available information from teleost IL-2 family cytokines and discussed implications in teleost immunity. Also, we described and discussed their expression profiles, receptors, signaling transductions and functions. In teleost, IL-2 family has 5 members (IL-2, IL-4/13, IL-7, IL-15, IL-21) without IL-9, and their receptors share a common γc subunit and include other 6 subunits (IL-2Rβ1/2, IL-4Rα1/2, IL-13Rα1/2, IL-7Rα, IL-15Rα, and IL-21Rα1/2). Some paralogues have changes in domain structure and show differential expression, modulation, functions. IL-2 family cytokines constitutively express in many immune associated tissues and are largely induced after pathogenic microbial stimulation. In general, there are relatively conserved functions in the IL-2 family throughout vertebrates, and many of the key IL-2 family members are important in lymphocyte proliferation and differentiation, development, inflammation from fishes to mammals. This review will give an update on the effective information of teleost IL-2 family cytokines. Thus, it will provide a source of reference for other researchers/readers and inspire further interest.

Care for Patients with Type-2 Chronic Rhinosinusitis

In the last 20 years, growing interest in chronic rhinosinusitis (CRS) has become evident in medical literature; nevertheless, it is still difficult to identify the real prevalence of the disease. Epidemiological studies are few and focused on heterogeneous populations and diagnostic methods. Recent research has contributed to identifying CRS as a disease characterized by heterogeneous clinical scenarios, high impact on quality of life, and elevated social costs. Patient stratification with phenotypes and identification of the pathobiological mechanism at the origin of the disease (endotype) and its comorbidities are pivotal in the diagnostic process, and they should be addressed in order to properly tailor treatment. A multidisciplinary approach, shared diagnostic and therapeutic data, and follow-up processes are therefore necessary. Oncological multidisciplinary boards offer models to imitate in accordance with the principles of precision medicine: tracing a diagnostic pathway with the purpose of identifying the patient’s immunological profile, monitoring therapeutical processes, abstaining from having only a single specialist involved in treatment, and placing the patient at the center of the therapeutic plan. Awareness and participation from the patient’s perspective are fundamental steps to optimize the clinical course, improve quality of life, and reduce the socioeconomic burden.

Molecular subclasses of preeclampsia characterized by a longitudinal maternal proteomics study: distinct biomarkers, disease pathways and options for prevention

OBJECTIVES

The heterogeneous nature of preeclampsia is a major obstacle to early screening and prevention, and a molecular taxonomy of disease is needed. We have previously identified four subclasses of preeclampsia based on first-trimester plasma proteomic profiles. Herein, we expanded this approach by using a more comprehensive panel of proteins profiled in longitudinal samples.

METHODS

Proteomic data collected longitudinally from plasma samples of women who developed preeclampsia (n=109) and of controls (n=90) were available from our previous report on 1,125 proteins. Consensus clustering was performed to identify subgroups of patients with preeclampsia based on data from five gestational-age intervals by using select interval-specific features. Demographic, clinical, and proteomic differences among clusters were determined. Differentially abundant proteins were used to identify cluster-specific perturbed KEGG pathways.

RESULTS

Four molecular clusters with different clinical phenotypes were discovered by longitudinal proteomic profiling. Cluster 1 involves metabolic and prothrombotic changes with high rates of early-onset preeclampsia and small-for-gestational-age neonates; Cluster 2 includes maternal anti-fetal rejection mechanisms and recurrent preeclampsia cases; Cluster 3 is associated with extracellular matrix regulation and comprises cases of mostly mild, late-onset preeclampsia; and Cluster 4 is characterized by angiogenic imbalance and a high prevalence of early-onset disease.

CONCLUSIONS

This study is an independent validation and further refining of molecular subclasses of preeclampsia identified by a different proteomic platform and study population. The results lay the groundwork for novel diagnostic and personalized tools of prevention.

Neonatal development of intestinal neuroimmune interactions

Interactions between the enteric nervous system (ENS), immune system, and gut microbiota regulate intestinal homeostasis in adults, but their development and role(s) in early life are relatively underexplored. In early life, these interactions are dynamic, because the mucosal immune system, microbiota, and the ENS are developing and influencing each other. Moreover, disrupting gut microbiota and gut immune system development, and potentially ENS development, by early-life antibiotic exposure increases the risk of diseases affecting the gut. Here, we review the development of the ENS and immune/epithelial cells, and identify potential critical periods for their interactions and development. We also highlight knowledge gaps that, when addressed, may help promote intestinal homeostasis, including in the settings of early-life antibiotic exposure.

Dupilumab: Advances in the off-label usage of IL4/IL13 antagonist in dermatoses

Type 2 immune response refers to a complicated series of immune responses characterized by Th2 polarization and Th2 cytokines secretion. The IgE secretion, airway hypersensitivity, and effector cell recruitment (eosinophils, mast cells, basophils) in skin lesion and peripheral blood stream could be upregulated during the activation of type 2 immune response. Th1/Th2 ratio, also referred as Th1/Th2 balance, represent the T lymphocytes immune pattern to a certain degree: Th1-dominated responses are often involved in intracellular infections (e.g., mycobacterium tuberculosis) and autoimmune diseases (e.g., Graves' disease) while Th2-dominated responses are involved in allergic conditions (e.g., atopic dermatitis, eczema), IgE mediated diseases (e.g., urticaria), and fibrotic dermatoses (e.g., keloids). Dupilumab, as one of the most widely applied Th2 cytokine inhibitors, could block the bioactivity of IL-14/IL-13 via competitively binding to the common IL-4Rα subunit shared by IL-4 and IL-13 receptors. In addition to the direct inhibition of type 2 response, dupilumab is also effective in autoimmune and some infectious skin diseases through indirect regulation of type 1 immune response. The pathological mechanism of Th2 responses and advanced clinical application of dupilumab in skin diseases will be summarized and discussed in the review.

Pruritus in Pregnancy

Pruritus in pregnancy is a common and burdensome symptom that may be a first sign of a pregnancy-specific pruritic disease (atopic eruption of pregnancy, polymorphic eruption of pregnancy, pemphigoid gestationis, and intrahepatic cholestasis in pregnancy) or a dermatosis coinciding with pregnancy by chance. Despite its high prevalence, pruritus is often underrated by physicians, and data regarding the safety profiles of drugs for pruritus are very limited. In this review, we illustrate the epidemiology, possible pathophysiology, clinical characteristics, and diagnostic workup of various pregnancy-related diseases and discuss antipruritic treatments. The prevalence of pruritus in pregnancy demonstrates the importance of symptom recognition and the need for an holistic approach, taking into account both the potential benefits for the patient and the potential risks to the fetus.

Cytokine Receptors-Regulators of Antimycobacterial Immune Response

Cytokine receptors are critical regulators of the antimycobacterial immune response, playing a key role in initiating and coordinating the recruitment and activation of immune cells during infection. They recognize and bind specific cytokines and are involved in inducing intracellular signal transduction pathways that regulate a diverse range of biological functions, including proliferation, differentiation, metabolism and cell growth. Due to mutations in cytokine receptor genes, defective signaling may contribute to increased susceptibility to mycobacteria, allowing the pathogens to avoid killing and immune surveillance. This paper provides an overview of cytokine receptors important for the innate and adaptive immune responses against mycobacteria and discusses the implications of receptor gene defects for the course of mycobacterial infection.

Molecular characterization, expression analysis and cellular location of IL-4/13 receptors in large yellow croaker (Larimichthys crocea)

Interleukin (IL)-4 and IL-13 are closely related class I cytokines that play key roles in the T helper (Th)-2 immune response via heterodimeric receptors. IL-4 signals via both the type I (IL-4Rα/γc) and type II (IL-4Rα/IL-13Rα1) receptor complexes, while IL-13 signals only via the type II receptor complex. IL-13Rα2 is traditionally considered a "decoy" receptor for IL-13. However, the IL-4/13 system and its response to pathogenic infection are still not fully understood in fish. In this study, we identified four IL-4/13 receptor subunit genes in the large yellow croaker (Larimichthys crocea): LcIL-4Rα1, LcIL-4Rα2, LcIL-13Rα1, and LcIL-13Rα2. Sequence analysis showed that these receptors possessed typical characteristic domains, including a signal peptide, two fibronectin type III (FN III)-like domains, and a transmembrane domain, but their cytoplasmic regions were not well conserved. The mRNA and protein of the four IL-4/13 receptors were constitutively expressed in all examined tissues of large yellow croaker. Their mRNAs were also detected in primary head kidney macrophages (PKMs), primary head kidney granulocytes (PKGs), and primary head kidney lymphocytes (PKLs). Immunofluorescence assay further showed that LcIL-4Rα and LcIL-13Rα1 were expressed on the membrane of IgM ⁺ B cells. After stimulation by Vibrio alginolyticus and poly (I:C) (a viral dsRNA mimic), the mRNA levels of LcIL-4/13 receptors were significantly upregulated in the head kidney and spleen. Their mRNA levels were also upregulated in head kidney leukocytes in response to poly (I:C) and lipopolysaccharide (LPS) treatment. Moreover, both recombinant LcIL-4/13A and LcIL-4/13B upregulated LcIL-4Rα1 and LcIL-4Rα2 in primary leukocytes, but only recombinant LcIL-4/13A upregulated LcIL-13Rα1 and LcIL-13Rα2. These results indicated that LcIL-4/13 receptors, containing conserved functional domains, may be involved in the IL-4/13-mediated immune response to pathogenic infections in the large yellow croaker.

IL-4Rα blockade reduces influenza-associated morbidity in a murine model of allergic asthma

Background

Asthma was identified as the most common comorbidity in hospitalized patients during the 2009 H1N1 influenza pandemic. We determined using a murine model of allergic asthma whether these mice experienced increased morbidity from pandemic H1N1 (pH1N1) viral infection and whether blockade of interleukin-4 receptor α (IL-4Rα), a critical mediator of T_h2 signalling, improved their outcomes.

Methods

Male BALB/c mice were intranasally sensitized with house dust mite antigen (Der p 1) for 2 weeks; the mice were then inoculated intranasally with a single dose of pandemic H1N1 (pH1N1). The mice were administered intraperitoneally anti-IL-4Rα through either a prophylactic or a therapeutic treatment strategy.

Results

Infection with pH1N1 of mice sensitized to house dust mite (HDM) led to a 24% loss in weight by day 7 of infection (versus 14% in non-sensitized mice; p < .05). This was accompanied by increased viral load in the airways and a dampened anti-viral host responses to the infection. Treatment of HDM sensitized mice with a monoclonal antibody against IL-4Rα prior to or following pH1N1 infection prevented the excess weight loss, reduced the viral load in the lungs and ameliorated airway eosinophilia and systemic inflammation related to the pH1N1 infection.

Conclusion

Together, these data implicate allergic asthma as a significant risk factor for H1N1-related morbidity and reveal a potential therapeutic role for IL-4Rα signalling blockade in reducing the severity of influenza infection in those with allergic airway disease.

Molecular mechanism of asthma and its novel molecular target therapeutic agent

Asthma is a chronic disease with major public health ramifications owing to its high morbidity and mortality rates, especially in severe and recurrent cases. Conventional therapeutic options could partially alleviate the burden of asthma, yet a novel approach is needed to completely control this condition. To do so, a comprehensive understanding of the molecular mechanism underlying asthma is essential to recognize and treat the major pathways that drive its pathophysiology. In this review, we will discuss the molecular mechanism of asthma, in particular focusing on the type of inflammatory responses it elicits, namely type 2 and non-type 2 asthma. Furthermore, we will discuss the novel therapeutic options that target the aberrant molecules found in asthma pathophysiology. We will specifically focus on the role of novel monoclonal antibody therapies recently developed, such as the anti-IgE, IL-5, IL-5Rα, and IL-4Rα antibodies, drugs that have been extensively studied preclinically and clinically.

Early chronic systemic inflammation and associations with cognitive performance after moderate to severe TBI

BACKGROUND

Cognitive dysfunction adversely effects multiple functional outcomes and social roles after TBI. We hypothesize that chronic systemic inflammation exacerbates cognitive deficits post-injury and diminishes functional cognition and quality of life (QOL). Yet few studies have examined relationships between inflammation and cognition after TBI. Associations between early chronic serum inflammatory biomarker levels, cognitive outcomes, and QOL 6-months and 12-months after moderate-to-severe TBI were identified using unweighted (uILS) and weighted (wILS) inflammatory load score (ILS) formation.

METHODS

Adults with moderate-to-severe TBI (n ​= ​157) completed neuropsychological testing, the Functional Impairment Measure Cognitive Subscale (FIM-Cog) and self-reported Percent Back to Normal scale 6 months (n ​= ​139) and 12 months (n ​= ​136) post-injury. Serial serum samples were collected 1-3 months post-TBI. Cognitive composite scores were created as equally weighted means of T-scores derived from a multidimensional neuropsychological test battery. Median inflammatory marker levels associated with 6-month and 12-month cognitive composite T-scores (p ​< ​0.10) were selected for ILS formation. Markers were quartiled, and quartile ranks were summed to generate an uILS. Marker-specific β-weights were derived using penalized ridge regression, multiplied by standardized marker levels, and summed to generate a wILS. ILS associations with cognitive composite scores were assessed using multivariable linear regression. Structural equation models assessed ILS influences on functional cognition and QOL using 12-month FIM-Cog and Percent Back to Normal scales.

RESULTS

ILS component markers included: IL-1β, TNF-α, sIL-4R, sIL-6R, RANTES, and MIP-1β. Increased sIL-4R levels were positively associated with overall cognitive composite T-scores in bivariate analyses, while remaining ILS markers were negatively associated with cognition. Multivariable receiver operator curves (ROC) showed uILS added 14.98% and 31.93% relative improvement in variance captured compared to the covariates only base model (age, sex, education, Glasgow Coma Scale score) when predicting cognitive composite scores at 6 and 12 months, respectively; wILS added 33.99% and 36.87% relative improvement in variance captured. Cognitive composite mediated wILS associations with FIM-Cog scores at 12 months, and both cognitive composite and FIM-Cog scores mediated wILS associations with QOL.

CONCLUSIONS

Early chronic inflammatory burden is associated with cognitive performance post-TBI. wILS explains greater variance in cognitive composite T-scores than uILS. Linking inflammatory burden associated with cognitive deficits to functional outcome post-TBI demonstrates the potential impact of immunotherapy interventions aimed at improving cognitive recovery post-TBI.

Non-hematopoietic IL-4Rα expression contributes to fructose-driven obesity and metabolic sequelae

OBJECTIVE

The risks of excess sugar intake in addition to high-fat diet consumption on immunopathogenesis of obesity-associated metabolic diseases are poorly defined. Interleukin-4 (IL-4) and IL-13 signaling via IL-4Rα regulates adipose tissue lipolysis, insulin sensitivity, and liver fibrosis in obesity. However, the contribution of IL-4Rα to sugar rich diet-driven obesity and metabolic sequelae remains unknown.

METHODS

WT, IL-4Rα-deficient (IL-4Rα^-/-) and STAT6-deficient mice (STAT6^-/-) male mice were fed low-fat chow, high fat (HF) or HF plus high carbohydrate (HC/fructose) diet (HF + HC). Analysis included quantification of: (i) body weight, adiposity, energy expenditure, fructose metabolism, fatty acid oxidation/synthesis, glucose dysmetabolism and hepatocellular damage; (ii) the contribution of the hematopoietic or non-hematopoietic IL-4Rα expression; and (iii) the relevance of IL-4Rα downstream canonical STAT6 signaling pathway in this setting.

RESULTS

We show that IL-4Rα regulated HF + HC diet-driven weight gain, whole body adiposity, adipose tissue inflammatory gene expression, energy expenditure, locomotor activity, glucose metabolism, hepatic steatosis, hepatic inflammatory gene expression and hepatocellular damage. These effects were potentially, and in part, dependent on non-hematopoietic IL-4Rα expression but were independent of direct STAT6 activation. Mechanistically, hepatic ketohexokinase-A and C expression was dependent on IL-4Rα, as it was reduced in IL-4Rα-deficient mice. KHK activity was also affected by HF + HC dietary challenge. Further, reduced expression/activity of KHK in IL-4Rα mice had a significant effect on fatty acid oxidation and fatty acid synthesis pathways.

CONCLUSION

Our findings highlight potential contribution of non-hematopoietic IL-4Rα activation of a non-canonical signaling pathway that regulates the HF + HC diet-driven induction of obesity and severity of obesity-associated sequelae.

Interleukin-25-mediated resistance against intestinal trematodes does not depend on the generation of Th2 responses

Background

The cytokine interleukin-25 (IL-25) is recognized as the most relevant initiator of protective T helper 2 (Th2) responses in intestinal helminth infections. This cytokine induces resistance against several species of intestinal helminths, including the trematode Echinostoma caproni. E. caproni has been extensively used as an experimental model to study the factors determining resistance to intestinal infections. In the study reported here, we assessed the role of IL-25 in the generation of resistance in mice infected with E. caproni.

Methods

The factors that determine the production of IL-25 in mice experimentally infected with E. caproni were determined, as were the consequences of IL-25 production in terms of polarization of the immune response and resistance to infection.

Results

Our results show that the role of IL-25 in the polarization of the immune response differs between the primary and secondary immune responses. IL-25 is required for the development of a Th2 phenotype in primary E. caproni infections, but it can also promote the differentiation to Th2 memory cell subsets that enhance type-2 immunity in memory responses. However, the development of Th2 responses does not induce resistance to infection. The Th2 phenotype does not elicit resistance, and IL-25 is responsible for the resistance regardless of its type-2 cytokine activity and activation of signal transducer and activator of transcription (STAT6). Alternative activation of macrophages induced by IL-25 can be implicated in the resistance to infection.

Conclusions

In contrast to primary infection, secondary infection elicits a type-2 immune response even in the absence of IL-25 expression. Despite the development of a type-2 response, mice are susceptible to secondary infection associated with the lack of IL-25. Resistance to infection is due to the production of IL-25, which acts autonomously from Th2 response in terms of parasite clearance.

Nonlethal Plasmodium yoelii Infection Drives Complex Patterns of Th2-Type Host Immunity and Mast Cell-Dependent Bacteremia

Malaria strongly predisposes to bacteremia, which is associated with sequestration of parasitized red blood cells and increased gastrointestinal permeability. The mechanisms underlying this disruption are poorly understood. Here, we evaluated the expression of factors associated with mast cell activation and malaria-associated bacteremia in a rodent model. C57BL/6J mice were infected with Plasmodium yoeliiyoelli 17XNL, and blood and tissues were collected over time to assay for circulating levels of bacterial 16S DNA, IgE, mast cell protease 1 (Mcpt-1) and Mcpt-4, Th1 and Th2 cytokines, and patterns of ileal mastocytosis and intestinal permeability.

Malaria strongly predisposes to bacteremia, which is associated with sequestration of parasitized red blood cells and increased gastrointestinal permeability. The mechanisms underlying this disruption are poorly understood. Here, we evaluated the expression of factors associated with mast cell activation and malaria-associated bacteremia in a rodent model. C57BL/6J mice were infected with Plasmodium yoeliiyoelli 17XNL, and blood and tissues were collected over time to assay for circulating levels of bacterial 16S DNA, IgE, mast cell protease 1 (Mcpt-1) and Mcpt-4, Th1 and Th2 cytokines, and patterns of ileal mastocytosis and intestinal permeability. The anti-inflammatory cytokines (interleukin-4 [IL-4], IL-6, and IL-10) and MCP-1/CCL2 were detected early after P. yoeliiyoelii 17XNL infection. This was followed by the appearance of IL-9 and IL-13, cytokines known for their roles in mast cell activation and growth-enhancing activity as well as IgE production. Later increases in circulating IgE, which can induce mast cell degranulation, as well as Mcpt-1 and Mcpt-4, were observed concurrently with bacteremia and increased intestinal permeability. These results suggest that P. yoeliiyoelii 17XNL infection induces the production of early cytokines that activate mast cells and drive IgE production, followed by elevated IgE, IL-9, and IL-13 that maintain and enhance mast cell activation while disrupting the protease/antiprotease balance in the intestine, contributing to epithelial damage and increased permeability.

Physiopathologie de la dermatite atopique et des autres maladies atopiques : une approche globale est-elle possible ?

Atopy is defined by the propensity to develop an exaggerated type-2 inflammatory response to environmental molecules. Clinically, atopy is diagnosed when atopic disease occurs: atopic dermatitis, food allergy, atopic asthma and allergic rhinitis and conjunctivitis. Whereas the classical "atopic march" is increasingly challenged through epidemiological studies, type-2 cellular inflammation is a characteristic shared by the atopic diseases. This inflammation can be innate (non-specific: eosinophils, mast cells, dendritic cells, innate lymphoid cells [ILC]), or adaptive (antigen-specific, involving T cells). Interleukins (IL-)4, 5 and 13 are major actors of type-2 inflammation and are mainly produced by ILC and T cells. The efficacy of treatments targeting these type-2 cytokines highlight the importance of type-2 inflammation in atopic diseases. However, several patients do not respond to type-2 targeting treatments, highlighting the presence of other actors in pathophysiology of atopic diseases: alteration of epithelial barrier, IgE-mediated allergic responses, type-17 inflammation. Thus, the term "endotype" can illustrate this diversity in pathophysiology. Finally, a global approach of atopic diseases, as type-2 inflammatory diseases, is fundamental, but not sufficient. An approach by endotype is advisable, in a personalized medicine perspective. © 2020 Elsevier Masson SAS. All rights reserved.

IL-4R alpha deficiency influences hippocampal-BDNF signaling pathway to impair reference memory

Like pro-inflammatory cytokines, the role of anti-inflammatory cytokines in both learning and memory has been investigated, revealing beneficial effects for both interleukin-4 and interleukin-13 via the common interleukin-4 receptor alpha chain complex. In this study, using the Morris water maze spatial task for cognition, we compared interleukin-4 receptor alpha- deficient mice and their ligands interleukin-4/ interleukin-13 double deficient mice, on a Balb/c background. We demonstrate that while interleukin-4/ interleukin-13 double deficient mice are significantly impaired in both learning and reference memory, interleukin-4 receptor alpha-deficiency impairs only reference memory, compared to the wild-type control mice. In order to better understand how interleukin-4 receptor alpha- deficient mice are able to learn but not remember, we investigated the BDNF/TrkB- and the ARC-signaling pathways. We show that interleukin-4 receptor alpha-deficiency disrupts activation of BDNF/TrkB- and ARC-signaling pathways during reference memory, while the pathway for spatial learning is spared.

In silico analysis reveals interrelation of enriched pathways and genes in type 1 diabetes

Type 1 diabetes (T1D) is a multifactorial, polygenic complex autoimmune disease damaging pancreatic islet β cells. Numerous genes linked to T1D have been discovered through genetical studies, GWAS and polymorphisms. Most genetical studies focused on independent genes while others overemphasized on SNPs. Here, a collective analysis of documented T1D-associated genes was performed using bioinformatics tools. Enriched biological pathways, functions, enrichment clustering, networks and interactomes were analysed. Besides, meta-analyses of T1D-associated genes and T1D-related genes from SNPs were investigated to find common genes, pathways, enrichment and interrelationships. Notable enriched pathways comprised of cytokine-mediated signalling, cytokine production, interferon gamma production, myeloid leukocyte activation, activation of immune response, lymphocyte activation, adaptive immune response, Th17 cell differentiation etc. Enrichment analysis of T1D-associated genes emphasized the role of immune-linked machineries in metabolism, disease progression and aetiology of type 1 diabetes. Interactome analysis revealed overrepresentation of T1D-associated genes compared with T1D-related genes from SNPs. MCODE components highlighted the significance of pathways linked to vitamin D metabolism, signalling by interleukins, toll-like receptors, chemokines, PD-1, NOTCH, antigen processes etc. About 153 genes from MCODE complexes representing enriched pathways of T1D-associated genes and T1D-related genes from SNPs play a crucial role and may be important for further investigations. The information may be valuable for designing precision medicine-based therapeutics.

Regulatory T cells in skin are uniquely poised to suppress profibrotic immune responses

At the center of fibrosing diseases is the aberrant activation of tissue fibroblasts. The cellular and molecular mechanisms of how the immune system augments fibroblast activation have been described; however, little is known about how the immune system controls fibroblast function in tissues. Here, we identify regulatory T cells (T_regs) as important regulators of fibroblast activation in skin. Bulk cell and single-cell analysis of T_regs in murine skin and lungs revealed that T_regs in skin are transcriptionally distinct and skewed toward T helper 2 (T_H2) differentiation. When compared with T_regs in lung, skin T_regs preferentially expressed high levels of GATA3, the master T_H2 transcription factor. Genes regulated by GATA3 were highly enriched in skin "T_H2 T_reg" subsets. In functional experiments, T_reg depletion resulted in a preferential increase in T_H2 cytokine production in skin. Both acute depletion and chronic reduction of T_regs resulted in spontaneous skin fibroblast activation, profibrotic gene expression, and dermal fibrosis, all of which were exacerbated in a bleomycin-induced murine model of skin sclerosis. Lineage-specific deletion of Gata3 in T_regs resulted in an exacerbation of T_H2 cytokine secretion that was preferential to skin, resulting in enhanced fibroblast activation and dermal fibrosis. Together, we demonstrate that T_regs play a critical role in regulating fibroblast activation in skin and do so by expressing a unique tissue-restricted transcriptional program that is mediated, at least in part, by GATA3.

Early-Life Respiratory Syncytial Virus Infection, Trained Immunity and Subsequent Pulmonary Diseases

Respiratory syncytial virus (RSV) is often the first clinically relevant pathogen encountered in life, with nearly all children infected by two years of age. Many studies have also linked early-life severe respiratory viral infection with more pathogenic immune responses later in life that lead to pulmonary diseases like childhood asthma. This phenomenon is thought to occur through long-term immune system alterations following early-life respiratory viral infection and may include local responses such as unresolved inflammation and/or direct structural or developmental modifications within the lung. Furthermore, systemic responses that could impact the bone marrow progenitors may be a significant cause of long-term alterations, through inflammatory mediators and shifts in metabolic profiles. Among these alterations may be changes in transcriptional and epigenetic programs that drive persistent modifications throughout life, leaving the immune system poised toward pathogenic responses upon secondary insult. This review will focus on early-life severe RSV infection and long-term alterations. Understanding these mechanisms will not only lead to better treatment options to limit initial RSV infection severity but also protect against the development of childhood asthma linked to severe respiratory viral infections.

Myeloid-Derived Suppressor Cell Subsets Drive Glioblastoma Growth in a Sex-Specific Manner

Myeloid-derived suppressor cells (MDSC) that block antitumor immunity are elevated in glioblastoma (GBM) patient blood and tumors. However, the distinct contributions of monocytic (mMDSC) versus granulocytic (gMDSC) subsets have yet to be determined. In mouse models of GBM, we observed that mMDSCs were enriched in the male tumors, whereas gMDSCs were elevated in the blood of females. Depletion of gMDSCs extended survival only in female mice. Using gene-expression signatures coupled with network medicine analysis, we demonstrated in preclinical models that mMDSCs could be targeted with antiproliferative agents in males, whereas gMDSC function could be inhibited by IL1β blockade in females. Analysis of patient data confirmed that proliferating mMDSCs were predominant in male tumors and that a high gMDSC/IL1β gene signature correlated with poor prognosis in female patients. These findings demonstrate that MDSC subsets differentially drive immune suppression in a sex-specific manner and can be leveraged for therapeutic intervention in GBM. SIGNIFICANCE: Sexual dimorphism at the level of MDSC subset prevalence, localization, and gene-expression profile constitutes a therapeutic opportunity. Our results indicate that chemotherapy can be used to target mMDSCs in males, whereas IL1 pathway inhibitors can provide benefit to females via inhibition of gMDSCs.See related commentary by Gabrilovich et al., p. 1100.This article is highlighted in the In This Issue feature, p. 1079.

Cytokines in Pain: Harnessing Endogenous Anti-Inflammatory Signaling for Improved Pain Management

Current pain therapeutics offer inadequate relief to patients with chronic pain. A growing literature supports that pro-inflammatory cytokine signaling between immune, glial, and neural cells is integral to the development of pathological pain. Modulation of these communications may hold the key to improved pain management. In this review we first offer an overview of the relationships between pro-inflammatory cytokine and chemokine signaling and pathological pain, with a focus on the actions of cytokines and chemokines in communication between glia (astrocytes and microglia), immune cells (macrophages and T cells), and neurons. These interactions will be discussed in relation to both peripheral and central nervous system locations. Several novel non-neuronal drug targets for controlling pain are emerging as highly promising, including non-viral IL-10 gene therapy, which offer the potential for substantial pain relief through localized modulation of targeted cytokine pathways. Preclinical investigation of the mechanisms underlying the success of IL-10 gene therapy revealed the unexpected discovery of the powerful anti-nociceptive anti-inflammatory properties of D-mannose, an adjuvant in the non-viral gene therapeutic formulation. This review will include gene therapeutic approaches showing the most promise in controlling pro-inflammatory signaling via increased expression of anti-inflammatory cytokines like interleukin-10 (IL-10) or IL-4, or by directly limiting the bioavailability of specific pro-inflammatory cytokines, as with tumor necrosis factor (TNF) by the TNF soluble receptor (TNFSR). Approaches that increase endogenous anti-inflammatory signaling may offer additional opportunities for pain therapeutic development in patients not candidates for gene therapy. Promising novel avenues discussed here include the disruption of lymphocyte function-associated antigen (LFA-1) activity, antagonism at the cannabinoid 2 receptor (CB2R), and toll-like receptor 4 (TLR4) antagonism. Given the partial efficacy of current drugs, new strategies to manipulate neuroimmune and cytokine interactions hold considerable promise.

Antibody blockade of Dectin-2 suppresses house dust mite-induced Th2 cytokine production in dendritic cell- and monocyte-depleted peripheral blood mononuclear cell co-cultures from asthma patients

Background

Dectin-2, which is a C-type lectin, interacts with the house dust mite (HDM) Dermatophagoides pteronyssinus allergen. This study aimed to investigate whether Dectin-2 blockade by antagonistic monoclonal antibodies (MoAbs) attenuates HDM-induced allergic responses.

Methods

Two anti-Dectin-2 MoAbs were generated and validated for specific binding to Dectin-2 Fc fusion protein (Dectin-2.Fc) and inhibition of Dectin-2.Fc/HDM interaction. Patients with asthma exhibiting high titers of anti-D. pteronyssinus IgE were enrolled. Peripheral blood mononuclear cells with depleted CD14⁺ monocytes were obtained from these patients and co-cultured with autologous monocyte-derived conventional dendritic cells in the presence of D. pteronyssinus or its group 2 allergens (Der p 2). Interleukin (IL)-5 and IL-13 levels in the culture supernatants were determined using ELISA in the presence or absence of anti-Dectin-2 MoAbs.

Results

Two MoAbs, 6A4G7 and 17A1D10, showed specific binding to recombinant Dectin-2.Fc and inhibited HDM binding to Dectin-2.Fc. Both anti-Dectin-2 MoAbs inhibited IL-5 and IL-13 production in co-cultures with Der p 2 stimulation in a dose-dependent manner. 6A4G7 and 17A1D10 (3 μg/mL) significantly inhibited Der p 2-induced (3 μg/mL) IL-5 production by 69.7 and 86.4% and IL-13 production by 84.0 and 81.4%, respectively. Moreover, this inhibitory effect of the two MoAbs remained significant in the presence of D. pteronyssinus.

Conclusions

Anti-Dectin-2 MoAbs significantly inhibited HDM-induced allergic responses in vitro and therefore have the potential to become therapeutic agents in mite-induced allergic diseases.

Development and characterization of monoclonal antibodies specific for chicken interleukin-13 and their neutralizing effects in chicken primary monocytes

Compared with mammals, the functionality of chicken cytokines is not well understood because of the unavailability of immune reagents. Mammalian interleukin (IL)-13 is an important Th2 type cytokine with well-known biological functions through its 2 receptors, IL-13 receptor (IL-13R)-α1 and IL-13Rα2. In the present study, we developed mouse monoclonal antibodies (mAb) against chIL-13 and further investigated their specificity in detecting endogenously produced chIL-13. Upon characterization of mAb using indirect ELISA and Western blot, the capture ELISA was developed for detecting chIL-13. Neutralizing effects were tested by measuring nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in primary chicken monocytes stimulated with chIL-13, lipopolysaccharide (LPS), chIL-13+LPS, or chIL-13+LPS+mAb. In addition, gene expression of chIL-13Rα1, chIL-13Rα2, and TGF-β1 was tested in chicken monocytes treated with chIL-13 or chIL-13+mAb. Based on indirect ELISA, 5 mAb that detected recombinant chIL-13 were identified, and all of them specifically detected recombinant chIL-13 protein by Western blotting. An optimal signal was obtained with 2 mAb (#9B11 and #10A2) in a pairing assay, and these 2 mAb were used in a capture assay. A neutralization assay further revealed that chIL-13 reduced LPS-stimulated NO production and iNOS expression in monocytes and macrophage cells, and the 2 mAb (#9B11 and #10A2) abrogated these effects. In addition, chIL-13-induced expressions of chIL-13Rα2 and TGF-β1 were neutralized by the 2 mAb. In summary, the present study showed that chIL-13 may be involved in the alternative activation of primary monocytes in chickens and that chIL-13 signaling may be regulated through chIL-13Rα2 binding and TGF-β1 secretion. Importantly, the newly developed anti-chIL-13 mAb will serve as valuable immune reagents for future studies on the biological activity of chIL-13 and its receptors.

Reduced expression of miR-146a in human bronchial epithelial cells alters neutrophil migration

Background

The role of miRNAs in the pathogenesis and determining the phenotypes of asthma is not fully elucidated. miR-146a has been previously shown to suppress inflammatory responses in different cells. In this study, we investigated the functions of miR-146a in human bronchial epithelial cells (HBECs) in association with neutrophilic, eosinophilic, and paucigranulocytic phenotypes of asthma.

Methods

Bronchial brushing specimens and brochial mucosal biopsy samples were collected from adult patients with asthma and from age- and gender-matched non-asthmatic individuals. The expression of miR-146a in bronchial brushing specimens, bronchial biopsy tissue sections or cultured primary bronchial epithelial cells was analyzed by RT-qPCR or by in situ hybridization. The expression of direct and indirect miR-146a target genes was determined by RT-qPCR or ELISA. The migration of neutrophils was studied by neutrophil chemotaxis assay and flow cytometry. For statistical analysis, unpaired two-way Student’s t test, one-way ANOVA or linear regression analysis were used.

Results

Reduced expression of miR-146a was found in bronchial brushing specimens from asthma patients as compared to non-asthmatics and irrespective of the phenotype of asthma. In the same samples, the neutrophil attracting chemokines IL-8 and CXCL1 showed increased expression in patients with neutrophilic asthma and increased IL-33 expression was found in patients with eosinophilic asthma. Linear regression analysis revealed a significant negative association between the expression of miR-146a in bronchial brushings and neutrophil cell counts in bronchoalveolar lavage fluid of patients with asthma. In bronchial biopsy specimens, the level of miR-146a was highest in the epithelium as determined with in situ hybridization. In primary conventional HBEC culture, the expression of miR-146a was induced in response to the stimulation with IL-17A, TNF-α, and IL-4. The mRNA expression and secretion of IL-8 and CXCL1 was inhibited in both stimulated and unstimulated HBECs transfected with miR-146a mimics. Supernatants from HBECs transfected with miR-146a had reduced capability of supporting neutrophil migration in neutrophil chemotaxis assay.

Conclusion

Our results suggest that decreased level of miR-146a in HBECs from patients with asthma may contribute to the development of neutrophilic phenotype of asthma.

A strategy for the selection of monovalent antibodies that span protein dimer interfaces

Ligand-induced dimerization is the predominant mechanism through which secreted proteins activate cell surface receptors to transmit essential biological signals. Cytokines are a large class of soluble proteins that dimerize transmembrane receptors into precise signaling topologies, but there is a need for alternative, engineerable ligand scaffolds that specifically recognize and stabilize these protein interactions. Recombinant antibodies can potentially serve as robust and versatile platforms for cytokine complex stabilization, and their specificity allows for tunable modulation of dimerization equilibrium. Here, we devised an evolutionary strategy to isolate monovalent antibody fragments that bridge together two different receptor subunits in a cytokine-receptor complex, precisely as the receptors are disposed in their natural signaling orientations. To do this, we screened a naive antibody library against a stabilized ligand-receptor ternary complex that acted as a "molecular cast" of the natural receptor dimer conformation. Our selections elicited "stapler" single-chain variable fragments (scFvs) of antibodies that specifically engage the interleukin-4 receptor heterodimer. The 3.1 Å resolution crystal structure of one such stapler revealed that, as intended, this scFv recognizes a composite epitope between the two receptors as they are positioned in the complex. Extending our approach, we evolved a stapler scFv that specifically binds to and stabilizes the interface between the interleukin-2 cytokine and one of its receptor subunits, leading to a 15-fold enhancement in interaction affinity. This demonstration that scFvs can be selected to recognize epitopes that span protein interfaces presents new opportunities to engineer structurally defined antibodies for a broad range of research and therapeutic applications.

Engineering of anti-human interleukin-4 receptor alpha antibodies with potent antagonistic activity

Development of antagonistic antibody (Ab) against interleukin-4 receptor alpha (IL-4Rα) subunit of IL-4/IL-13 receptors is a promising therapeutic strategy for T helper 2 (TH2)-mediated allergic diseases such as asthma and atopic dermatitis. Here we isolated anti-human IL-4Rα antagonistic Abs from a large yeast surface-displayed human Ab library and further engineered their complementarity-determining regions to improve the affinity using yeast display technology, finally generating a candidate Ab, 4R34.1.19. When reformatted as human IgG1 form, 4R34.1.19 specifically bound to IL-4Rα with a high affinity (KD ≈ 178 pM) and effectively blocked IL-4- and IL-13-dependent signaling in a reporter cell system at a comparable level to that of the clinically approved anti-IL-4Rα dupilumab Ab analogue. Epitope mapping by alanine scanning mutagenesis revealed that 4R34.1.19 mainly bound to IL-4 binding sites on IL-4Rα with different epitopes from those of dupilumab analogue. Further, 4R34.1.19 efficiently inhibited IL-4-dependent proliferation of T cells among human peripheral blood mononuclear cells and suppressed the differentiation of naïve CD4+ T cells from healthy donors and asthmatic patients into TH2 cells, the activities of which were comparable to those of dupilumab analogue. Our work demonstrates that both affinity and epitope are critical factors for the efficacy of anti-IL-4Rα antagonistic Abs.

Fine-Tuning Cytokine Signals

Cytokines are secreted or otherwise released polypeptide factors that exert autocrine and/or paracrine actions, with most cytokines acting in the immune and/or hematopoietic system. They are typically pleiotropic, controlling development, cell growth, survival, and/or differentiation. Correspondingly, cytokines are clinically important, and augmenting or attenuating cytokine signals can have deleterious or therapeutic effects. Besides physiological fine-tuning of cytokine signals, altering the nature or potency of the signal can be important in pathophysiological responses and can also provide novel therapeutic approaches. Here, we give an overview of cytokines, their signaling and actions, and the physiological mechanisms and pharmacologic strategies to fine-tune their actions. In particular, the differential utilization of STAT proteins by a single cytokine or by different cytokines and STAT dimerization versus tetramerization are physiological mechanisms of fine-tuning, whereas anticytokine and anticytokine receptor antibodies and cytokines with altered activities, including cytokine superagonists, partial agonists, and antagonists, represent new ways of fine-tuning cytokine signals.

Identification and expression analysis of IL-4/13 receptors in grass carp Ctenopharyngodon idella

Interleukin (IL)-4 and IL-13 are T helper 2 (Th2) cytokines with pleiotropic functions. IL-4 interacts with two receptors consisting of IL-4Rα/γ chain receptor (γC) and IL-4Rα/IL-13Rα1. In contrast, IL-13 binds to IL-13Rα2 but also shares the receptor complex containing IL-4Rα/IL-13Rα1. In fish, two IL-4/13 homologs have been identified but their phylogenetic relationships with IL-4 and IL-13 are ambiguous. In this study, we identified six putative IL-4/13 receptor homologs in grass carp, including γC1, γC2, IL-4Rα1, IL-13Rα1, IL-13Rα2 and a soluble form of IL-4Rα2. Comparative sequence analyses revealed that these receptors possess conserved characteristic domains and the genes encoding them share conserved gene synteny with their human counterparts. All six receptors contain a cytokine binding homology domain (CHD) and two fibronectin type Ⅲ (FNⅢ) like domains, with IL-13Rα1 and IL-13Rα2 harbouring an extra Ig-like domain preceding the CHD domain. Interestingly, grass carp IL-13Rα1 and IL-13Rα2 lack the characteristic WSXWS motif, a typical feature of mammalian type I cytokine receptors. The IL-4/13 receptor genes are differentially expressed in tissues and primary leukocytes of head kidney and can be modulated by Flavobacterium cloumnare (F. cloumnare), suggesting they are involved in immune response against F. cloumnare infection.

The tertiary structure of γc cytokines dictates receptor sharing

The γc family of cytokines comprising interleukin-2 (IL-2), IL-4, IL-7, IL-9, IL-15 and IL-2 is an important group of 4-helix bundle cytokines that signals through receptors incorporating the common gamma chain (γc). These cytokines are involved in lymphocyte biology and their specific functions are contingent on binding to cognate receptor chains. Here, we examined the structural relationships between γc cytokines, aiming to understand the basis for receptor chain usage and sharing. To that end, we obtained tertiary structures of human and mouse γc cytokines plus two other related cytokines, IL-13 and TSLP, which share receptors with IL-4 and IL-7, respectively. Subsequently, we compared the cytokine 3D-structures introducing a structural similarity score that grouped γc cytokines in a manner that mirrored the relationships dictated by receptor sharing. Unlike previously thought, we identified that IL-9 is more closely related to IL-2 and IL-15 than to IL-7, which is actually the most distant member of the γc family of cytokines. Moreover, we found that all the members of the γc family of cytokines share the topology of short-chain 4-helix bundle cytokines but IL-7 that with TSLP has the topology of long-chain 4-helix bundle cytokines. We also carried out Maximun-Likehood and Bayesian phylogenetic analyses that supported these results at the amino acid sequence level. Overall, our findings are of paramount relevance to understand receptor sharing among γc cytokines and can lead to the discovery of new cytokine receptor partners.

Characterization of cryptic allosteric site at IL-4Rα: New paradigm towards IL-4/IL-4R inhibition

Interleukin-4(IL-4), an anti-inflammatory cytokine, plays significant role in pathogenesis of various diseases such as asthma, tumors, and HIV infections. These responses are mediated by expression of IL-4R (receptor) on various hematopoietic and non-hematopoietic cells surfaces. To date, the X-ray crystal structure of unbound (i.e. free) IL-4R is not reported which hampers active research on the molecular interaction mechanism between IL-4 and IL-4R. To investigate the missing gaps about stable binding mode of IL-4 and drug-ability of IL-4R active site, modelling and molecular dynamics (MD) simulation of IL-4/IL-4R complex was performed. Drug-ability of the target protein changed after modelling the loop region near C-terminal of IL-4R protein. This led to the identification of a novel druggable site other than the reported interfacial site. Our analysis showed that the modelled residues Ser111 and Ser164-Lys167 are part of newly discovered allosteric site, which underwent major fluctuation after association with its ligand protein (IL-4). The results indicated possible role of this cryptic allosteric site in IL-4/IL-4R signaling pathway that might help us to block IL-4/IL-4R association to prevent various allergic and malignant diseases.

Mapping Determinants of Cytokine Signaling via Protein Engineering

Cytokines comprise a large family of secreted ligands that are critical for the regulation of immune homeostasis. Cytokines initiate signaling via dimerization or oligomerization of the cognate receptor subunits, triggering the activation of the Janus Kinases (JAKs)/ signal transducer and activator of transcription (STATs) pathway and the induction of specific gene expression programs and bioactivities. Deregulation of cytokines or their downstream signaling pathways are at the root of many human disorders including autoimmunity and cancer. Identifying and understanding the mechanistic principles that govern cytokine signaling will, therefore, be highly important in order to harness the therapeutic potential of cytokines. In this review, we will analyze how biophysical (ligand-receptor binding geometry and affinity) and cellular (receptor trafficking and intracellular abundance of signaling molecules) parameters shape the cytokine signalosome and cytokine functional pleiotropy; from the initial cytokine binding to its receptor to the degradation of the cytokine receptor complex in the proteasome and/or lysosome. We will also discuss how combining advanced protein engineering with detailed signaling and functional studies has opened promising avenues to tackle complex questions in the cytokine signaling field.

Molecular Endotypes Contribute to the Heterogeneity of Asthma

Diagnosis and management of asthma is commonly implemented based on clinical assessment. Although these nonmolecular biomarkers have been useful, limited resolution of the heterogeneity among asthmatic patients and little information regarding the underlying pathobiology of disease in individuals have been provided. Molecular endotying using global transcriptome expression profiling associated with clinical features of asthma has improved our understanding of disease mechanisms, risk assessment of asthma exacerbations, and treatment responses, especially in patients with type 2 inflammation. Further advances in establishing pathobiological subgroups, bioactive pathways, and true disease endotypes hold potential for a more personalized medical approach in asthmatic patients.

Interleukin 4/13 receptors: An overview of genes, expression and functional role in teleost fish

In superior vertebrates, Interleukin 4 (IL-4) and Interleukin 13 (IL-13) play key and diverse roles to support immune responses acting on cell surface receptors. When stimulated, receptors activate intracellular signalling cascades switching cell phenotypes according to stimuli. In teleost fish, Interleukin 4/13 (IL-4/13) is the ancestral family cytokine related to both IL-4 and IL-13. Every private and common receptor subunit for IL-4/13 have in fish at least two paralogues and, as in mammals, soluble forms are also part of the receptor system. Reports for findings of fish IL-4/13 receptors have covered comparative analysis, transcriptomic profiles and to a lesser extent, functional analysis regarding ligand-receptor interactions and their biological effects. This review addresses available information from fish IL-4/13 receptors and discusses overall implications on teleost immunity, summarized gene induction strategies and pathogen-induced gene modulation, which may be useful tools to enhance immune response. Additionally, we present novel coding sequences for Atlantic salmon (Salmo salar) common gamma chain receptor (γC), Interleukin 13 receptor alpha 1A chain (IL-13Rα1A) and Interleukin 13 receptor alpha 1B chain (IL-13Rα1B).

A nested case-control study of 277 prediagnostic serum cytokines and glioma

Recent research shows bidirectional communication between the normal brain and the peripheral immune system. Glioma is a primary brain tumor characterized by systemic immunosuppression. To better understand gliomagenesis, we evaluated associations between 277 prediagnostic serum cytokines and glioma. We used glioma (n = 487) and matched control (n = 487) specimens from the Janus Serum Bank Cohort in Oslo, Norway. Conditional logistic regression allowed us to identify those cytokines that were individually associated with glioma. Next, we used heat maps to compare case to control Pearson correlation matrices of 12 cytokines modeled in an in silico study of the interaction between the microenvironment and the tumor. We did the same for case-control correlation matrices of lasso-selected cytokines and all 277 cytokines in the data set. Cytokines related to glioma risk (P ≤ .05) more than 10 years before diagnosis are sIL10RB, VEGF, beta-Catenin and CCL22. LIF was associated with decreased glioma risk within five years before glioma diagnosis (odds ratio (OR) = 0.47, 95% confidence interval (CI) = 0.23, 0.94). After adjustment for cytokines above, the previously observed interaction between IL4 and sIL4RA persisted (> 20 years before diagnosis, OR = 1.72, 95% CI = 1.20, 2.47). In addition, during this period, case correlations among 12 cytokines were weaker than were those among controls. This pattern was also observed among 30 lasso- selected cytokines and all 277 cytokines. We identified four cytokines and one interaction term that were independently related to glioma risk. We have documented prediagnostic changes in serum cytokine levels that may reflect the presence of a preclinical tumor.

The cytokine polymorphisms affecting Th1/Th2 increase the susceptibility to, and severity of, chronic ITP

BACKGROUND

T-helper cell type 1 (Th1) polarization in chronic immune thrombocytopenia (cITP) has been reported at the protein and mRNA levels. We evaluated the impact of Th1/Th2 cytokine and cytokine receptor functional polymorphisms on both susceptibility to, and severity of, cITP. We analysed IFN-γ + 874 T/A, IFN-γR -611G/A, IL-4 -590C/T, and IL-4Rα Q576R polymorphisms in 126 cITP patients (male/female: 34/92; median age: 47.7 years) and 202 healthy control donors. Genotyping was determined by PCR and direct sequencing. The Th1/Th2 ratio was detected in peripheral blood mononuclear cells via flow cytometry.

RESULTS

cITP patients had a higher frequency of the IL-4Rα 576 non-QQ genotype compared to healthy subjects (P = 0.04). cITP patients with the IFN-γ +874 non-AA genotype (high expression type) showed more severe thrombocytopenia than those with the AA genotype (P < 0.05). cITP patients had a significantly higher Th1/Th2 ratio than control patients (P < 0.01); this ratio was inversely correlated with platelet counts. Furthermore, patients with both IFN-γ +874 non-AA genotype (high expression type) and IFN-γR -611 non-AA genotype (high-function type) had a significantly higher Th1/Th2 ratio (P < 0.05).

CONCLUSIONS

The cytokine polymorphisms affecting Th1/Th2 increase the susceptibility to, and severity of, chronic ITP.

Synthekines are surrogate cytokine and growth factor agonists that compel signaling through non-natural receptor dimers

Cytokine and growth-factor ligands typically signal through homo- or hetero-dimeric cell surface receptors via Janus Kinase (JAK/TYK), or Receptor Tyrosine Kinase (RTK)-mediated trans-phosphorylation. However, the number of receptor dimer pairings occurring in nature is limited to those driven by natural ligands encoded within our genome. We have engineered synthethic cytokines (synthekines) that drive formation of cytokine receptor dimer pairings that are not formed by endogenous cytokines and that are not found in nature, and which activate distinct signaling programs. We show that a wide range of non-natural cytokine receptor hetero-dimers are competent to elicit a signaling output. We engineered synthekine ligands that assembled IL-2Rβ/IL-4Rα or IL-4Rα/IFNAR2 receptor heterodimers, that do not occur naturally, triggering signaling and functional responses distinct from those activated by the endogenous cytokines IL-2, IL-4, and IFN. Furthermore, hybrid synthekine ligands that dimerized a JAK/STAT cytokine receptor with a receptor tyrosine kinase (RTK) also elicited a signaling response. Synthekines represent a new family of synthetic ligands with pre-defined receptors, but 'orphan' functions, that enable the full combinatorial scope of dimeric signaling receptors encoded within the human genome to be exploited for basic research and drug discovery.

IL4Rα and ADAM33 as genetic markers in asthma exacerbations and type-2 inflammatory endotype

BACKGROUND

Genetic markers of susceptibility to asthma exacerbations in adults remain unclear.

OBJECTIVE

To identify genetic markers of asthma exacerbations, particularly in patients with type-2 inflammatory endotype.

METHODS

In this observational study of patients enrolled in the Kinki Hokuriku Airway disease Conference multicenter study, frequency of exacerbations requiring systemic corticosteroids during 2 years after enrolment and associated risk factors was determined. For genetic marker analysis, interleukin-4 receptor α (IL4RA) rs8832 and a disintegrin and metalloprotease 33 (ADAM33) S_2 (rs528557), T_1 (rs2280091), T_2 (rs2280090), and V_4 (rs2787094) variants were included. Elevated serum periostin levels at enrolment (≥95 ng/mL, defined as type-2 inflammatory endotype) were considered in the analysis.

RESULTS

Among 217 patients who were successfully followed up for 2 years after enrolment, 60 patients showed at least one asthma exacerbation during the 2 years. Airflow limitation (%FEV₁ <80%) and recent exacerbations but not genetic variants were identified as risk markers of exacerbations. A total of 27 patients showed type-2 inflammatory endotype (serum periostin ≥95 ng/mL at enrolment) and subsequent exacerbations; risk factors in these patients were airflow limitation (odds ratio, 6.51; 95% confidence interval (CI): 2.37-18.6; P=.0003), GG genotype of IL4RA rs8832 (odds ratio, 4.01; 95% CI: 1.47-11.0; P=.007), and A allele of ADAM33 T_2 (odds ratio, 2.81; 95% CI: 1.05-7.67; P=.04) by multivariate analysis. In addition, GG genotype of IL4RA rs8832 was associated with type-2 endotype, whereas A allele of ADAM33 T_2 was associated with mixed type of eosinophilic/type-2 and neutrophilic inflammations.

CONCLUSIONS AND CLINICAL RELEVANCE

IL4RA and ADAM33 variants may be risk markers of asthma exacerbations in type-2 inflammatory endotype. Precise endotyping may facilitate the identification of genetic risk markers of asthma exacerbations.

IL4 Primes the Dynamics of Breast Cancer Progression via DUSP4 Inhibition

The tumor microenvironment supplies proinflammatory cytokines favoring a permissive milieu for cancer cell growth and invasive behavior. Here we show how breast cancer progression is facilitated by IL4 secreted by adipose tissue and estrogen receptor-positive and triple-negative breast cancer cell types. Blocking autocrine and paracrine IL4 signaling with the IL4Rα antagonist IL4DM compromised breast cancer cell proliferation, invasion, and tumor growth by downregulating MAPK pathway activity. IL4DM reduced numbers of CD44⁺/CD24^- cancer stem-like cells and elevated expression of the dual specificity phosphatase DUSP4 by inhibiting NF-κB. Enforced expression of DUSP4 drove conversion of metastatic cells to nonmetastatic cells. Mechanistically, RNAi-mediated attenuation of DUSP4 activated the ERK and p38 MAPK pathways, increased stem-like properties, and spawned metastatic capacity. Targeting IL4 signaling sensitized breast cancer cells to anticancer therapy and strengthened immune responses by enhancing the number of IFNγ-positive CTLs. Our results showed the role of IL4 in promoting breast cancer aggressiveness and how its targeting may improve the efficacy of current therapies. Cancer Res; 77(12); 3268-79. ©2017 AACR.

IL-13-Mediated Regulation of Learning and Memory

The role of proinflammatory cytokines in cognitive function has been investigated with both beneficial and possible detrimental effects, depending on the cytokine. More recently, the type 2 IL-4 has been demonstrated to play a role in cognition. In this study, using the Morris water maze task, we demonstrate that IL-13-deficient mice are significantly impaired in working memory as well as attenuated reference memory, both functions essential for effective complex learning. During the learning process, wild-type mice increased the number of CD4⁺ T cells in the meninges and production of IL-13, whereas neither Morris water maze-trained IL-4 nor trained IL-13-deficient mice were able to increase CD4⁺ T cells in the meninges. Mechanistically, we showed that IL-13 is able to stimulate primary astrocytes to produce brain-derived neurotrophic factor, which does foster cognitive functions. Moreover, Morris water maze-trained wild-type mice were able to increase astrocyte-produced glial fibrillary acidic protein in the hippocampus, which was impaired in Morris water maze-trained IL-4- and IL-13-deficient mice. Collectively, this study strongly suggests that the Th2 cytokines, not only IL-4 but also IL-13, are involved in cognitive functions by stimulating astrocytes from the meninges and hippocampus. These results may be important for future development of therapeutic approaches associated with neurologic disorders such as Parkinson disease-associated dementia and HIV-associated dementia among others.

Interleukin 4 and interleukin 13 downregulate the lipopolysaccharide-mediated inflammatory response by human gestation-associated tissues

Inflammation is a key feature of preterm and term labor. Proinflammatory mediators are produced by gestation-associated tissues in response to pathogen-associated molecular patterns and damage-associated molecular patterns. Interleukin (IL)4, IL10, and IL13 are anti-inflammatory cytokines with potential as anti-inflammatory therapies to prevent preterm birth. The objective of this study was to determine if IL4 and IL13 exert anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated production of proinflammatory cytokines produced by human term gestation-associated tissues (placenta, choriodecidua, and amnion). Both IL4 and IL13 reduced LPS-stimulated IL1B and macrophage inflammatory protein1A; this effect diminished with delay to exposure to either cytokine. There was no effect on LPS-stimulated prostaglandin production. Interleukin 4 receptor alpha (IL4RA) was expressed throughout the placenta, choriodecidua, and amnion, and the inhibitory effects of IL4 and IL13 were IL4RA dependent. Combined IL4 and IL13 did not enhance the anti-inflammatory potential of either cytokine; however, a combination of IL4 and IL10 had a greater anti-inflammatory effect than either cytokine alone. These findings demonstrate that human term gestation-associated tissues are responsive to the anti-inflammatory cytokines IL4 and IL13, which could downregulate LPS-induced cytokine production in these tissues. Anti-inflammatory cytokines might offer an adjunct to existing therapeutics to prevent adverse obstetric outcome.